U.S. Pat. No. 4,396,494 is directed to upgrading heavy oil by catalytic hydrotreating and solvent deasphalting. The recovered bitumen from the deasphalting step can be recycled to the hydrotreater.
EP 99141 teaches a process for the production of deasphalted oils and distillates e.g., the catalytic hydrotreatment of an asphaltene containing hydrocarbon feed mixture with the hydrotreated product being separated by distillation into one or more distillate fractions and a heavy residue. The residue is then subjected to two-stage solvent deasphalting to produce a low quality oil, a high quality oil and an asphaltic bitumen. The low quality oil and the asphaltic bitumen may be recycled to the hydrotreater.